JPS588651A - Electrographic processing method for printing plate - Google Patents

Abstract

PURPOSE:To avoid the uneven density of a plate by using extended pattern for an original. CONSTITUTION:A density signal is obtained with a reader head 20 via photoelectric conversion from an origin 10 formed by extending a pattern by a required length. This signal is converted into a digital density signal with an A/D converter 21. Then, the density signal is processed with a engraving curve corrector 26 through channel selectors 25 and 27 and then, inputted into a computer. The CPU35 performs a computation to correct and outputs the density signal with the uneven density corrected with at the vertical and horizontal splices, which is stored in a memory device 40 every one scanning line through a CPU data output I/F 36 and a memory input register 37.

Description

[Detailed Description of the Invention] The present invention scans the entire document for printing a horizontally continuous multi-sided pattern, and prints the horizontally continuous multi-sided pattern on a plate-making cylinder based on the obtained density signal. This is a device that electronically forms a plate-making image, especially 1.
This eliminates the difference in density gradation at the seam where one unit pattern changes to the next unit pattern.

Traditionally, for example, endless patterns have been used as printing patterns for building materials (veneer boards, flooring, wallpaper, etc.), printed clothing, etc., or patterns in which multiple identical patterns are arranged horizontally and the seams of the patterns are continuous. Certain horizontally continuous multi-sided designs are often used.

Such a vertical endless pattern, horizontal continuous Ing,
几, manufactured by He11), etc. are mentioned.

In addition, as a document on the electronic plate making device, for example, Japanese Patent Application Laid-open No. 1983
There are publications such as JP-A-122309, JP-A-51-111101, and JP-A-51-112601.

In order to make a plate for printing a vertical endless pattern (hereinafter simply referred to as an endless pattern) using this electronic plate-making device, a manuscript for the endless pattern with a continuous front and rear edge is created, and the plate is made to become a plate. The plate is made by engraving the cylinder while scanning it so that the front end and rear end of the cylinder are exactly aligned.

In addition, when printing a horizontally continuous multi-sided pattern (hereinafter simply referred to as a multi-sided pattern), create a multi-sided pattern original with a pattern whose left and right edges are continuous, and place the right and left edges in a plate-making cylinder to ensure that the right and left edges are accurate. The plate is made by engraving while scanning to match the image. By the way, when performing plate making to print such endless designs and/or multi-sided designs, if there is a density difference between the front edge and rear edge and/or left edge and right edge of the original to be printed, the plate making cylinder When printing is carried out with such a printing plate, the seams of the resulting printed image tend to have a difference in density gradation at the line or seam where the edges of the plate-made image are joined. A step difference in density gradation occurs.

Even if the difference in density at the edge of the document is so small that it cannot be measured with a densitometer, the difference in density gradation at the seam in the actual printed matter will be very noticeable. be. However, when a document is manufactured, a slight difference in density often occurs between the front end and rear end and/or the left end and right end due to, for example, uneven development.

In such cases, failures in manuscript production are rarely noticed before printing, and are often noticed only after printing. In such cases, the printed version or manuscript may be revised, or the manuscript may be rewritten.
In any case, it takes a lot of time and money, and it is a big problem to make such continuous patterns. Due to these circumstances, it is difficult to eliminate the seams between the front and rear ends of endless plates (hereinafter simply referred to as vertical joints) and the joints between the left and right ends between unit designs in multi-sided designs (hereinafter simply referred to as horizontal joints). It was strongly desired.

In the case of making a plate for printing a multi-sided design, the present invention provides a method for making a plate-making image formed on a plate-making cylinder even if there is a density difference between the continuous left and right edges of the document. The drawbacks of the prior art are solved by making a plate so that no density difference appears at the vertical joints between unit designs.

An embodiment of the present invention will be explained below. Generally, in this type of electronic plate-making device, designs that are endless designs and multi-sided designs are often made, so in the embodiments described below, the above-mentioned endless and multi-sided designs are used. An example of making a plate will be described.

Further, in explaining the present invention, the description of the techniques known in the electronic plate making apparatus as described above will be simplified.

As shown in FIG. 1, the manuscript 001, which has an endless pattern and is used for printing a multi-sided pattern, has a front end (p+) and a rear end (B+) that form a continuous endless pattern, and furthermore, the rear end In (I3), the design is continuously extended by an interval (BC) compared to the conventional manuscript.The extended area (BC) is the number of samples as will be described later. The width is equivalent to 200 pieces (approximately 3 squares).The pattern in this section (BC) is the same as the section (F'G
) is the same as the pattern. Furthermore, the design of the manuscript (IQ+) is a multi-sided design in which the left end (D and right end -) are continuous,
At the right end, the document is continuously extended by a section (n, s) compared to the conventional document. This extended section (R8) has a width corresponding to 200 scanning lines (approximately 3 crrL), as will be described later.

The document (1) made in this way is transferred to the reading cylinder (11
), and read the density on the document by rotating the cylinder (111) and sequentially moving the reading head (A) from left to right (that is, by scanning the document (11 vertically)) (see Figure 2). , the obtained concentration signal is transferred to the cylinder αD
It is converted into a digital density signal by sampling in synchronization with the rotation of the sensor. Here, the number of halftone dots per line per circumference of the plate-making cylinder that becomes the plate is a value determined by the diameter of the plate-making cylinder, the halftone dot density, etc., and this number of halftone dots (Nl is This is the same as the number of samplings per line. Further, the number of samplings (nl) in the section (BC) is constant at 200 in this embodiment.

The number of scanning lines (6) between sections (L) is a value determined by the width of the unit pattern, the line number density of plate making, etc. Further, the number of scanning lines (kl) in the section (S) is constant at 200 lines in this embodiment.

In this way, the manuscript σQ has an interval (LS) of ten lines and an interval (FC) of N ten! A single sample is scanned and converted into a digital density signal to obtain density data.

Now, on the X-th line from the left end, let the Y-th data from the front end C1 be D(X:Y') (x, y are natural numbers, 1≦X
≦−)−k, 1≦Y≦N+n).

D(1≦X≦; 1≦Y≦N) can be said to be the density data used as is in the conventional technology, and D(1≦
X≦;N+1≦Y≦N1n) can be considered to be data added to eliminate density differences at vertical joints in endless plate making.

Further, D (+k for K+1≦X≦; 1≦Y≦N) can be said to be data added to eliminate density differences at horizontal seams in plate making of multi-sided designs.
゛In addition, D (K+1≦X≦-4-; N+t≦Y≦N10n
) can be said to be data that has been added to eliminate the difference in density between vertical and horizontal joints in plate making, which is an endless pattern and a multi-sided pattern.

Now, in order to eliminate the density difference at the vertical seam of the endless pattern, a correction calculation is performed on the data of one section (F()) using the data of the section (BC).

Such a correction operation may be performed by gradually converting the data in one section (CBC) to the data in the other section (FG).

If the corrected data is U, then for example n = 200 (the above is the formula of the first group). Furthermore, the data of the section (GB) is not corrected for the seam and is made as a value as it is. .

By making a plate based on the density data subjected to the correction calculation in this manner, the difference in density at the # seam is eliminated.

Also, to eliminate the density difference at the horizontal seam of a multi-sided pattern,
It is sufficient to perform a correction calculation of the interval (LM) using the data of the interval (R8).

Such a correction operation can be performed by gradually converting the data of one section to the data of the other section, similarly to the correction of the vertical seam.

If the corrected data is ``, then, for example, = 200 (if X is even, if X is odd, 1)'(X;Y) = I)'(X+1;Y)However, 1≦X≦200 9 - (The above is the equation of the second group.) Note that the data of the section (MR) is printed as the value of the mark without being corrected for the seam.

Here, in order to eliminate the density difference between the vertical seam of the endless pattern and the horizontal seam of the multi-sided pattern, either correction calculation may be performed first, but it is sufficient to perform both correction calculations in sequence. In the embodiment of the plate-making apparatus described later, the vertical seam correction calculation is performed first.

Data modified in this way (1≦X≦r()
, (1≦Y≦,N), so that the front edge and rear edge, and the left edge and right edge of the cylindrical plate-making cylinder match (by making a plate, the front edge and rear edge, left edge and right edge of the manuscript are aligned). Even if there is a density difference, the vertical seam in the endless pattern,
The difference in density at the horizontal joint between unit designs in a multi-sided design is eliminated, and no difference in density appears at the vertical and horizontal joints of printed matter printed with such a printing plate.

Next, an electronic plate making apparatus for correcting vertical seams and horizontal seams as described above will be described.

As shown in FIG. 2, the reading cylinder Ql) is loaded with a document (1) in which the design is extended by a required length from the conventional document as described above.Then, while rotating the reading cylinder αυ, photoelectric conversion move the reading head (a) with the
A photoelectric converter photoelectrically converts the reflected light from the original (1 (l) to obtain a density signal. The obtained signal is sent to an A/D converter ring, and the A/D converter +211 samples it and converts it into a 10-bit signal. The serial 10-bit digital density signal thus obtained is input to a serial/parallel converter (221) and converted into a parallel digital signal.

It is further converted into a digital density signal having 8 bits, ie, 256 density levels, by a 10-bit to 78-bit converter.

Next, the density signal is input to the engraving curve corrector (A) via the channel selector @gradient, and the engraving curve corrector (C) performs signal processing such as negative/positive conversion and gradation correction as necessary. later entered into the computer. The channel selectors (c) and (c) are interlocked, and are provided with channels 1 to 8 as shown in the figure, which allow multiple reading heads and multiple engraving heads to operate in parallel. For example, a large number of repeating patterns in the horizontal direction can be made simultaneously.

However, since such a configuration is well known in the Heliocrissograph 200 type mentioned above, a description thereof will be omitted.

The concentration signal outputted via the channel selector (2) is sent to the CPU (
C) is done manually.

This CPU (g) is for performing calculations for eliminating the density difference between the vertical seams and/or the horizontal seams described above.

A condition setting device (c) is connected to this CPU (35), and when the diameter of the plate-making cylinder, the width of the unit pattern of the multi-sided pattern, the line number density, etc. are set in the condition setting device, the setting values are The number of samples N and the number of lines K are calculated and CP
It is input to U (to). Furthermore, the CPU (g) stores the density signals of the document section (BS), the document section (LM), and the horizontally corrected section (LM) in order to perform calculations to eliminate the density difference at the horizontal seam. Memory bag for Wff
A011) is connected. This memory bag fu A Q
Since <I) requires a large storage capacity, a magnetic disk type storage device is used in this embodiment.

In the plate making of multi-sided designs, first of all, the sections (
The density signal obtained by scanning the section (TtS) is stored in the storage device A (foundation), and then when the section (1, R), which is the first unit design, is made, the section (LM, ) is scanned. The signals of the interval (LM, ) and the interval (BS) stored in this way are used to create a
The signal of the interval (LM) that has been laterally corrected by calculating the group equation is stored in the storage device A, and the signal of the interval (LM) after that is
) is a memory bag when it comes to plate making! A plate is made by reading out the density signal of the section (LM) in which the horizontal correction calculation has been performed, which is stored in AC(4). In addition, in order to perform correction calculations for both vertical seams and horizontal seams, the sections (几S) and (LM
) When storing the density signal, the CPU (c) may perform vertical correction calculations and then store the density signal in the storage device.

In this way, CPUQ! 9, correction calculations are performed on the equations of the first group, the equations of the second group, etc., and a density signal corrected for the density level difference at the vertical seam and horizontal seam is output, and the density signal is sent to the CPU data output I/F. (to), is input to the storage device B (4G) via the memory manual register 07), and is input to the storage device B (4G) for each scanning line.
Stored in G.

This storage device B (41) uses core memory in this embodiment.

The density signal stored in this storage device B (41) is read out in synchronization with the rotation of the plate-making cylinder (451), and the read density signal is input to the D/A converter (43) to determine the density value for each halftone dot. is converted into an analog signal corresponding to

After being converted into an analog signal, it is sent to the recording head (C), where it is engraved into the plate-making cylinder (49) in a step-like manner. Form a prepress image.

The manner in which this apparatus is used will be described below in the case where both vertical and horizontal seams are to be corrected.

First, scan the section (R8) of the document Ql in advance,
The data is stored in the storage device A (corporate) while performing correction calculations for vertical seams.

Next, the section (LM) of the document is scanned, vertical seam correction calculations are performed, and the obtained density signal is stored in the storage device Ap.
4) and form a plate-making image on a plate-making cylinder.

Next, a section (MR) of the document is scanned, a vertical seam correction calculation is performed, and a plate-making image is formed on a plate-making cylinder. When the plate making for this section (MR) is completed, storage device A C1
4) The section (
A horizontal direction correction calculation is performed based on the signals of the interval (LM) and the interval (I'tS), and the density signal of the interval (LM) in which the vertical and horizontal joints have been revised is stored in the storage device A04).

Next, from the storage device AC34), the signal of the section (LM) in which the mesh and horizontal correction calculations have been performed is read out for plate making, and then the signal obtained by scanning the section (MR) of the manuscript is used to correct the vertical seam. Perform calculations and make plates.

Thereafter, by repeating this process a necessary number of times, a printing plate for endless and multi-sided pattern printing is obtained.

Since the present invention has the above configuration, it has excellent practical effects as shown below. That is, in conventional plate making of horizontally continuous multi-sided designs, density steps often appeared on the printing plate due to minute density differences between the left and right edges of the original, which was a big problem, but with the present invention, this problem has been solved. For example, even if a document with density differences is used, no density difference will appear on the plate, so there is no need to re-make the plate or re-create the original, and this has an extremely excellent practical effect.

Moreover, in such plate making, it is sufficient to use a manuscript with a slightly longer design than in the past, so it does not require much more expense than in conventional plate making. Also, in terms of equipment,
The present invention has extremely excellent practical effects, such as being able to be manufactured by adding a computer, a storage device, etc. to a conventional electronic plate making device.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a plan view of a document used in the present invention, and FIG. 2 is a block diagram of a plate-making apparatus. α[...Original αυ...Reading cylinder C...Reading head Q...A/D converter (221...S/P
Converter 0th floor...10 bit/8 bit converter Q■
匈...Channel selector Qθ...Engraving curve corrector (3α (3η...Register (to)...Condition setting device G+) (n...Interface (Foundation)
...Storage device A l351...C'PU (41.
...Storage device B (43)...D/A converter (4
Interrogation recording head (451...plate-making cylinder patent applicant 17-

Claims (1)

[Claims] 1) In the electronic plate-making method for making printing plates that print horizontally continuous multi-sided designs, all documents in which the same design as the opposite side is extended for the required length on the right edge (or left edge) as a manuscript. Prepare the manuscript, scan the original, obtain a strong signal, and use the density data of the extended section in the obtained fC concentration data to correct the corresponding density data at the other end, and this correction calculation is performed on one side. Based on the t-density signal subjected to correction calculations in this way, the plate-making image is entirely formed on the plate-making cylinder so that the left and right edges thereof exactly match. Electronic prepress method.